Aromatic sulfonic acid esters containing an amino group



Patented Oct. 28, 1952 STATES PATENT ,V-QOFFICE ABOMATIC S ULFONIC ACID ESTERS C TAJNING AN AMINO GROUP "Willy Widmet,, Bttmingen,Land AlfreclFasciati, Basel, Switzerland, assignors to. :Ciba Limited,

Halogen (H) .R1SOR| c6011 0 in which R1 represents a benzene radical in which the halogen atom and the substituent --COOH are in ortho-position relatively to each other, and R2 represents a benzene radical containing a carboxy group, with ammonia, at a temperature exceeding 100 C., in the presence of metallic copper.

The halogen atom in the compound of the above general formula may be, for example, a bromine atom or advantageously a chlorine atom. The radical R2 may contain other substituents than the carboxy group, for example, a methyl group or a chlorine atom.

The substituents halogen and COOI-I are in ortho-position relatively to each other in the benzene radical R1, and the carboxy group in the radical R2 ispreferably in o-position relatively to the a a linkage. The radical .-SO'2O--R2 may be bound to the benzene radical R1 in any desired position, for example, in para-position relatively to the substituent COOH or to the halogen atom.

and

O OH

are valuable starting materials.

Basel, Switzerland, a Swissfirm No Drawing. Application June 19, 1951, Serial i No. 232,448. .In Switzerland'JlulylS,1949.. v

. The compounds.corresponding to the general formula fir'st'inentioned above can be prepared by methods in themselves known. Thus,.for example, sulfonic acidchloridesof'the general formula 7 I r I Halogen 12 -50 01 g p coon in which 1R1 has the meaning given above, may be'reacted with hydroxybenzoic' acids such aslhydroxybenzene-2-carboxylic acid or l-hydro'xy- -methyl-benzene-Qecarbcxylic acid by the usual methods of esterification.

As examples of compounds of the formula first mentioned above, which are used as startingma terials' in the present invention, there may be mentioned: 2- chlorobenzene '5 sulfonic acid phenyl ester-1 :2"-dicarboxylic acid, and 2-chlorobenzene-5-sulfonic acid- (4 methylor 4- chloro) -phenyl ester-1:2' dicarboxy1ic acid.

The reaction with ammoniainaccordancewith the present process is advantageously carried out by using a considerable excess of ammonia above the quantity theoretically required and vvorking in an aqueousor alcoholic medium, but with as high a concentration of ammonia as possible. The reaction is conducted at temperatures above C., for example, at temperatures ranging from -130 C., and advantageously in a closed vessel. In order to obtain a smooth reaction a small quantity of metallic-copper is tobe added.

Good results are generally obtained by mixing the sulfonic acid ester to be used as starting material with a large excess of an aqueous ammonia solution of 20-30 per cent. strength with the addition of a little copper-powder, and carrying out the reaction in a stirring autoclave for several hours at the necessary temperature. I

The aromatic sulfonic acid esters containing an amino group obtainable by the present process aref new and correspond to the general formula in which Rifrepresents a benzene radical "inwhich the substituentsI-IzN- and -COO I-I are in orthoposition relatively to one another, R2 represents a benzene radical containing a carboxy group.

. These sulfonic acid esters are valuable -,inter-- good yield into the corresponding sulfonic acid esters containing an amino group by the action of ammonia without the ester group being attacked.

The following example illustrates the invenparts by weight to parts by volume being the same i as that of the kilogram to the liter.

Example 156.5 parts of 2-chlorobenzene l-carboxylic acid are slowly introduced at room temperature" while stirring into 350.0 parts of chlorosulfonic acid, and the mixture is heated at 95100 C. for .4

The solution so obtained is then poured hours. on to 1500 parts of ice, while stirring, andthe resulting white precipitate of 2-chlorobenzene-5- sulfonic acid chloride-l-carboxylic acid is separated by filtering with suction and'washed with ice water. j

The 2-chlorobenzene-5 -sulfonic acid chloridel-carboxylic acid so obtained is suspended in 1000 parts of ice water and mixed with 138.0 parts of Z-hydroxybenzene-l-carboxylic acid. To the suspension, while it is energetically stirred, a sodium hydroxide solution of 30 per cent. strength is slowly introduced in portions until the reaction is slightly but permanently alkaline to phenol phthalein. The temperature rises during the ad dition to 35 C; The whole is allowed to cool from 35 C. to 20 C. for a few hours while stir.- ring. The resulting solution is then acidified with concentrated hydrochloric acid, and the we I COQH NHz I O= COOH is a pale grey-brown powder which dissolves very easily in dilute alkalis. It may be used for the preparation of azo dyestuffs, for example, in the following manner:

33.7 parts of 2-aminobenzene-5-sulfonic acid phenyl ester-1:2-dicarboxylic acid are dissolved in 400 parts of water and 8 parts of sodium hydroxide. 6.9 parts of sodium nitrite are added to the solution, and the latter is then slowly introducd in portions at 5-8 G. into 100 parts by volume of a 5N-solution of hydrochloric acid.

Sufficient sodium carbonate is added to the suspension of the diazo compound to produce only a weakly acid reaction to Congo, andthe whole is added at 5-10 C. to a solution of 17.4; parts of 1 (4 chloro) s phenyl 3 methyl 5 spyrazolone in 500 parts of water and '25 'partsof sodium carbonate.

in dilute'sodium carbonate solution with a yellow coloration, in 1 pure concentrated sulfuric acid The tha is stirred 8-10 C". until the diazo reaction disappears, the dyestuff is completely precipitated by the addition of sodium chloride,

' separated by filtration and dried.

The dyestuff is a yellow powder which dissolves with a greenish yellow coloration and dyes wool from an ecetic acid bath yellow tints, which when .afterchromed, are transformed into a very fast brownish yellow; I The dyestuif is also excellently suited for dyeing by the single bath chroming process, and in this case also very fast slightly brownish yellow tints are obtained.

i In the manner described in this example the '2 aminobenzene 5 sulfonic acid ifmeth yD-phenyl ester-1:2'-dicarboxylic acid is obtained from ,2-chlorobenzene-5 sulfonic acid chloride-l-carboxylic acid and -methyl-lhydroxybenzene-2 carboxylic acid;

What we claim is:

1. A compound of the formula COOH in which R represents a benzene radical containing a carboxy group.

2. The compound of the formula NHi 3. The compound of the formula COOH NH: 9 a

WILLY WIDMER. i

ALFRED FASCIATI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,646,785 Duisberg Oct. 25, 1927 OTHER REFERENCES Groggins, Unit Processes in Organic Synthesis, second edition, sixth impression, pp. 200, 201, 309 (1938). 

1. A COMPOUND OF THE FORMULA 